Obesity (overweight), elevated blood pressure and increased serum cholesterol levels are the main causes of cardiovascular diseases which, in turn, are the leading cause of premature deaths in all industrialized societies. In spite of enormous efforts, the average body weight of inhabitants of the industrialized societies is continuously increasing, and no effective and practical method has been found to decrease serum cholesterol and elevated blood pressure in the whole population rather than in the individuals with the highest risk only. The present invention represents a dietary method by which the above-mentioned main ailments of the industrialized societies can be practically and effectively controlled. A high serum cholesterol level is a major risk factor of coronary heart disease (also called ischaemic heart disease) which, in turn, is the leading cause of death in industrialized countries. Lowering of serum cholesterol levels decreases the incidence of coronary heart disease.
It is well-known that some plant sterols, especially beta-sitosterol and its hardened form, beta-sitostanol, decrease the absorption of dietary cholesterol from the intestine. A recent invention (PCT/FI91/00139 which corresponds to WO 92/19640) made a significant contribution to a more efficient use of the principle of the inhibition of cholesterol absorption. However, the plant sterols and stanols are able to inhibit the absorption of dietary cholesterol only if they are present in the intestine simultaneously with the dietary cholesterol. In the invention in accordance with PCT/FI91/00139, a stanol ester is incorporated in vegetable fat which is essentially free of cholesterol. Furthermore, the main embodiment of said invention is margarine which is commonly used with bread, a food item also essentially free of cholesterol. It has to be borne in mind that, by far the most prominent sources of dietary cholesterol are eggs, meats and meat products, as well as butter and other dairy products.
Moreover, the rate of the endogenous synthesis of cholesterol may be a more important factor in the long-term control of serum cholesterol level than the intestinal absorption. Unfortunately, the use of sitostanol according to PCT/FI91/00139, or increased intake of other compounds which decrease the gastrointestinal absorption of dietary cholesterol, increase the endogenous synthesis of cholesterol remarkably, by 34.9% in a recent study (T. A. Miettinen, Duodecim 1996; 112: 1149-1154). Therefore, the increased synthesis of cholesterol in the body markedly counteracts the serum cholesterol lowering effect of sitostanol and that of the natural plant sterols. These factors may explain the fact that, according to long-term experience, increased intakes of these sterols and stanols lead to a mild fall of serum cholesterol levels only. It should also be borne in mind that, the detrimental effects of a given serum cholesterol level on blood vessels and cardiovascular diseases may be remarkably influenced by several, partly hitherto unidentified factors.